Furnace



W. M. DUNCAN ml. 1 WM FURNACE Filed Feb. 10 1921 2 Shams-Sheet 1 WILLIAMM. DUNCAN, OF ALTON, ILLINOIS.

FURNACE.

Applicationfiled February 10, .1921. Serial No. 444,018.

To all whom it may concern: 7

Be it known that I, WILLIAM M. DUNCAN, a citizen of the United States ofAmerica, and a resident of Alton, in the county of Madison, State ofIllinois, have invented certain new and useful Improvements in Furnaces,of which the following is a full, clear, and exact description,reference being had to the accompanying drawings, forming part of thisspecification. H

This invention relates to improvements in furnaces, and moreparticularly to a furnace provided with draft boxes surrounded by a eachdraft box is open at the top for the discharge of draft through the fuelsupporting portion of the grate, and this allows the ashesttogether withfine particles of fuel to drop into the draft box. As a means forremoving the ashes from the draft box, I have shown a conveyor wherebyashes are transmitted from the bottom of the draft box and through anash out-let at one end .of the box. This ash conveyor is preferably inthe form of a rotary screw arranged longitudinally of the draft box atthebottom thereof and extending into the ash outlet.

A further object of the invention is to prevent leakage of draft throughthe ash outlet, and this is preferably accomplished by forming an ashsealin said outlet, the ashes being pushed into the outlet so as toclose the same at a point beyond the ash conveyor.

Another object is to provide an ash discharge device adapted to'becarried by a portable mechanical stoker, and having detachable elementsallowing the portable stoker to be moved into and out of the furnace.

Fig. I is a longitudinal section, illustrating a mechanical stokerembodying the features of this invention, the middle portion of theapparatus being broken away.

Fig. II is a transverse section of the apparatus shown in Fig. I.

To illustrate the invention, I have shown a mechanical stoker comprisingan: endless chain grate A supported between side frame members 1 mountedon wheels 2. The chain grate comprises many grate links 3 connected bymeans of pivot rods 4.- arranged transversely of the grate. A powershaft 5 (Fig.

I), supported by the side frames 1, is provided with any desired numberof sprocket wheels 6 for transmitting movement to the endless chaingrate. The chain grate passes around the sprocket wheels 6 and alsoaround a plain idle wheel, or roll 7, the latter being mounted on ashaft 8. The fuel passes from a hopper 9 to the top face of the grate,as indicated by arrows in Fig. I.

The furnace is provided with suitable side walls B and B, includingrefractory members 10 located adjacent to the side margins of the grate.The lower portion of the side wall B is hollow, as shown in Fig. II, toprovide an inlet passageway 11 for the draft. 12 designates draft boxessurrounded by the traveling grate and extending from a side frame 1 atone side of the grate to the frame 1 at the other side. All of theseboxes are open at the top to provide for the delivery of the draft tothe grate.

One end of each draft box is provided. with an intake nipple 13 fortheadmission of draftand the opposite end. is provided with a nipple 14 forthe discharge of ashes. Since the grate is supported by a portableframe, including the side frame members 1 adapted to be moved into andout of the fur nace, the nipples 13 and 14 are detachable, each nipplebeing tele scoped with one of the side frame members 1 and also with oneof the furnace walls.

The ash passageway 15 is formed in the lower portion of the furnace wallB so as to communicate with all of the nipples 14, and a rotary screwconveyor 16 is located in the bottom of this passageway.

, Each draft box 12 contains an ash couveyor 17 'whereby ashes aretransmitted along the bottom of the draft box and pushed into its ashoutlet nipple lt, said conveyor 17 being in the form of a rotary screwarranged longitudinally of the draft box at the bottom thereof andextending into the outlet nipple 14;. The screw conveyor 17 terminatesin the outlet nipple, and the external diameter of the screw isapproximately equal to the internal diameter of the nipple.

One end of each screw conveyor 17 is rotatably mounted in a bearing 18extending from one of the side frame members 1, and the same end isprovided with a socket 19. A rotary operating shaft 20, extendingthrough the furnace wall B, is enserted into the socket l9, and thisoperating shaft can be withdrawn from the socket to permit removal ofthe grate-supporting frame which is supported by the WhBGlS'Q.

The screw conveyors 17 are rotated at suitable intervals for the purposeof removing the ashes which accumulate in the draft boxes, the ashesbeing pushed into the outlet nipples 14 where they accumulate beyond theends ofthe'screw conveyors 1.7 to form seals which prevent the escape ofdraft through-the ash outlets; All of the nipples 14L communicate withthe ash passageway 15, but the ash seals in the nipples let preventthe-escape; of draft from one draft box to another;

Thescrew conveyor 16 is operated at intervals to're-n'iove ashes from.theash passagew-ay-lfi;

I claim:

1. A furnace provided with an endless traveling grate, a draft boxsurrounded by said grate,.said draft box being open at the top forthe'discharge of draft through the fuel-supporting portion of the grate,said draft'box also having an ash outlet at one of itsends,.and aconveyor whereby ashes are transmitted along the. bottom of said draftbox and pushed into said ash outlet, so as to form a seal in saidoutlet, said conveyor comprising a rotary screw arranged longitudinallyof said draft box at the bottom thereof and terminating in said ashoutlet.

2. A furnace provided with an endless traveling grate, a draft boxsurrounded by said grate, said draft box being open at the top for thedischarge'of draft through the fue'l supportingportion of the grate,said draft: box also having an-ash outlet at one of its endsfand aconveyor whereby ashes are transmitted alongthe bottom of said draft boxand pushed into said ash outlet, soas to form a seal in said outlet,said con veyor comprising a rotary screw arranged longitudinally. ofsaid draft box at the bottom thereof and terminating .in said ashoutlet, said ash outlet being cylindrical and approximately equal indiameter to the rotary screw.

3. Afurnace provided with an endless traveling grate, a draft boxsurroundedby 7 said 'grate,said :draft box being open at the top forthedischarge'ofdraft through the.

fuel-supporting portion of the grate, said draft box also having an ashoutlet at one of its ends, and a conveyor whereby ashes are transmittedalong. the bottom of said draft box and pushed into said ash outlet, soasto form a seal in said outlet, said conveyor comprising a rotary screwarranged longitudinally of said draft box at the bottom thereof andterminating in said ash outlet, the furnace being provided with an ashpassageway communicatingwith said ash outlet, and means for forcingashes through said ash passageway.

at. A furnace provided with side walls; an endless traveling gratesupported between said side walls, draft boxes surrounded by saidendless grate, each of said draft boxes beingopen at the top for thedischarge of draft through the fuel supporting portion of the grate,one-of said side walls having a draft passageway and the other side wallbeing provided with an ash passageway, one end of each draft box havinga draft inlet communicating with said draft passageway and the other endhaving an ash outlet leading to said ash passageway, and conveyorswhereby ashes are transmitted from the bottoms of the draft boxes andinto the-ash outlets, so as to form ash seals in said ash outlets. v

5. A furnace provided with side walls, an endless traveling gratesupported between said side walls, draft boxes surrounded by saidendless'grate, each of said draft boxes being open at the top for thedischarge of draft through the fuel supporting portion of the. grate,one of said side walls having a draft passageway and the other side wallbeing provided with'an ash passageway, one end of each draft box havinga draft inlet communicating with said draft passageway and the other endhaving an ash outlet leading to said ash passageway, and conveyorswhereby ashes are transmitted from the bottomsof theTdraft-boxes andinto the ash outlets,so as to form ash seals in said ash butlets, saidconveyors comprising rotary screws each arranged longitudinally of oneof the draft boxes at the'bottom thereof and terminating at the'ashoutlet.

In testimony that I clainrthe foregoing I hereunto aflix my signature. I

ILLI-AM M. DUNCAN.

